The design of school learning environments can foster, or hinder, the teaching and learning of 21st century skills. By the time students complete their compulsory education, they will have spent many thousands of hours within school buildings. The same holds true for their teachers and school leaders who all too often are obliged to adapt to existing layouts in schools, rather than shape them actively. The OECD School User Survey: Improving Learning Spaces Together gives voice to those who use schools on a daily basis. This unique OECD tool consists of three self-assessment questionnaires designed for students, teachers and school leaders. They can be used to collect and triangulate evidence on the actual use of learning spaces, as well as to solicit user perspectives. Survey results can be used at the school level to support continuous improvement and the intelligent use or refurbishment of educational facilities. They can provide deeper insights into how physical learning environments shape teaching practices and affect students’ learning outcomes and well-being.